Catch mechanism



C. B. ELERDING CATCH MECHANISM July 20, 1954 2 Sheets-Sheet 1 Filed June 9, 1952 INVENTOR. C4200: fifzaeame ill- Ill: I'll C. B. ELERDING CATCH MECHANISM July 20, 1954 2 Sheets-Sheet 2 Filed June 9, 1952 INVENTOR. ULRUQE 5.5L EEO/N6 HTTOKNEIJ Patented July 20, 1954 UNITED STATES e ENT OFFICE CATCH MECHANISM Claude B; Elerding, Seattle, Wash.

Application June 9, 1952, Serial No. 292,543

6 Claims.

This invention relates to improvements in mechanisms which are generally known as catches or as latch devices, and it has reference to a latch mechanism for supporting a hinged lid or cover at any one of a plurality of raised or open positions. More specificially, the invention relates to a latching mechanism that is designed for use in connection with a school desk equipped with a top that is hingedly mounted for tilting adjustment; the present latching mechanism serving as a means for supporting the desk top at any one of a plurality of predetermined positions of inclination to which it may be adjusted to suit the convenience of the user.

It is the principal object of the present invention to provide a simple, relatively inexpensive and positively acting latch mechanism of the above character that is rendered automatic in its setting and releasing operations through the raising and lowering movements of the desk top to which it is attached.

Another object of the invention is to provide a latching mechanism including a pivoted latch dog that is mounted on a relatively stationary member of the desk, and a latch bar that is attached at one end to the desk top, and which moves relative to the pivoted dog incident to raising and lowering of the desk top; the bar being formed with notches in spaced relationship therealong, in which the latch dog is selectively engageable to retain the desk top at the desired inclination, and the mechanism being further characterized by the inclusion of novel devices associated with the bar and with the latch dog which make possible the automatic releaseof the dog for a change in adjustment of the desk top and also an automatic engagement of the dog to secure an adjustment after it has been made.

Still further objects and advantages of the present invention reside in the specific details of construction of, and in the combination of those parts that co-act for the automatic release and resetting of the latch dog.

In accomplishing the above mentioned and other objects of the invention, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Fig. 1 is a side view of a portion of a desk having a top that is mounted for tilting adjustment and is adapted to be selectively supported at different positions of inclination by a latching mechanism embodying the improvements of the present invention therein.

Fig. 2 is top view of the latching mechanism as 2 applied to the desk; the top of the desk being indicated only in dotted lines for a better showing of the latching mechanism.

Fig. 3 is a side view of the latch bar and latch dog in the relationship they assume with the desk top in a fully lowered position.

Fig. 4 is a cross-section of the latch bar and do as seen on the line 44 in Fig. 3.

Fig. 5 is a fragmental elevation of a portionof the latch bar and latchdog, showing the latter in holding contact with a shoulder on the bar; the parts being in the relationship in which they are shown in full lines in Fig. 1.

Fig. 6 is a view similar to that of Fig. 5, illustrating the upward actuation of the latch dog as effected by a limited upward adjustment of the desk top, preparatory to lowering it in its position of support.

Fig. 7 is a similar view illustrating the re-engaging of the latch dog with the latch barfor support of the desk top at the lowered position of support.

Fig. 8 is a cross-section of the latch bar and dog, as seen on line 8-8 in Fig. 6.

Fig. 9 is a perspective view of parts of the latch dog in disassembled relationship.

As a showing of a typical use of the present mechanism, it has been illustrated in connection with a school desk that is equipped with a top that is hingedly mounted for adjustment about the hinge axis to difierent angles of inclination and supported at any one of a plurality of definite or pre-determined positions. It is to be understood, however, that the present mechanism is applicable to various other articles, for example, it may be used in connection with the lid of a trunk, chest or other container, or as a means of support for the door panel of the rear compartment of an automobile; the present illustrations, however, being typical of the various adaptations and uses of the mechanism. v

Referring more in detail to the drawingsf In Fig. l, a school desk is designated generally by reference numeral Ill. It comprises a frame structure having a cross member ii to which the desk top or cover is is hingedly attached by a hinge designated in its entirety by numeral is. The hinge provides that the top can be adjusted upwardly from a horizontal position of rest on the desk frame, for support at any one of a p1urality of selected angles of inclination.

The present latch mechanism comprises two principal parts which are herein referred to, respectively, as the latch bar and the latch dog. The latch bar, which is designated in its entirety by reference numeral l6, comprises a fiat, rigid and somewhat elongated bar, preferably of metal, pivotally attached at its forward end by a pivot pin I! to a bracket 18 that, in turn, is rigidly attached to the under side of the desk top at a substantial distance from the hinge as has been shown in Fig. l. The bar 16 is formed with a straight, longitudinal slot [9, extending substantially the full length of thebar. Extending through this slotis a pivot member 29, which may be a pin, bolt, stud or shaft that is rigidly mounted in the frame structure of the desk parallel with the hinge axis, as seen in Fig.2. The. position of the latch bar l6, as thus attached to the desk top is such that in theraising and lowering of the desk top, the bar is caused to move longitudinally in guided support by thepivot member 20. In the present instance. when the lid is in its lowered, horizontal position of rest onthe desk frame, the bar It assumes the horizontal. dotted line. position in. which it is shown in Fig. 1, and.whenltheilidisraised to a 45 angle, the bar willkassume. the substantially verticalfull lineposition. Raising of desk top beyond about a 50 angle...is,.in.this instance,

limited bythelow-er end of.lthe.bar. slot I9- engaging with the pivot stud 20.

Associated withthe-latchbar lfi'and pivot 20 is the latch dog whichin Figs. 1,2 and 3 isdesignated in its entirety. by reference. numeral 25. More specifically described, the latch dog comprises a frame member that .preferably .ishlanked asra single piecefromsheet metal, .then bent substantially toiu -form. In itsfinalform it comprises spaced, parallel oppositesidezplates -25,.connected acrossthe forward edges of. their lower ends, with reference to its showing in thepresent drawings, by an integral.strap 2 l. A-t'the rear edges,- of thelower ends. of these. side plates, wings 28-28. are inwardly. turned into. end. to end contact. Extended'between the upper end portions of the side plates 26-46. of. thelatch dog, is a tubular bushing 29.; the. opposite. end

portions of which-extend .through and are secured. in the plates as shownin Fig, 8.. This tubular bushing is rotatably fittedon the pivot member lib-audit extends throughtheslot l9. oithe .bar l6. Medially of its ends, the bushing-is formed with a squared portion. 29:11. that-iscontained in the slot. Adjacent its opposite. ends, .the bushing is slightly reduced-in externaldiameter to prov-ide mounting portionsriortheplates Mi-2 5, and toformshoulders against whichtheplates may beengaged to be thereby heldin .a definite spaced relationship.

Mounted on the bushing, .at opposite. sides .of its squared mediahportionifiar, and. flatly engaged against the opposite side .faces .of the bar. is, are fiat washers 30 328;. Disposed. against these washers are fiat spring. metal strips -3.l3l., each strip-having a circular; enlargement3'l' at one endformed with acentralhole 3112, for receiving the end portion. of the bushing, therethrough. Each :spring strip extendsalong-the inside face of the correspondingtside plate of the latchdog to the lower end of-thelatter andis therezconfined between the cross strap-2.1 andan inturned wing 2 B. Mounted under. compression. on the bushing, between the side platesrof thelatch-dog andt-he head portions of :the: spring-stripstl .3 I, are corrugated spring washers -35,- whichyieldingly resist outward springing,of the spring strips, as

assembled with thelatchdog. Zllhenormal relationship of .springstri'ps T3] -3] 'Itolthe side. members of the latch dog is as shown in Fig. 8.

The latch bar [6, as seen in Figs. 1 and 3, is formed in its lower edge, at predetermined intervals therealong, with recesses or notches 49; each notch having one edge perpendicular to the edge of the bar to provide an abutment shoulder 4|, and having a gradually sloping and rather elongated opposite edge 2. All shoulders 4i, as noted in Fig. 1, face toward the lower end of the bar and they are so located in: the bar that whencross strap 2'? of the latch dog'isengaged with any one of them, the desk top will be supported at a definite angle of inclination.

While I have herein shown the bar 15 as being equipped with only three notches, more or less might be employed as desired or required.

It will be understood that when the top [3 is raised andthe cross strap 2? of the latch dog is holdingly engaged against the end shoulder of a notch, for example as noted in Fig. l or in Fig. 5, the desk top will be supported in an inclined position. Also, it will beun'd'erstood'that to lower the desk top,.from' any inclined position of support, it will be'necessary that the'latch dog'be' disengaged from .the'sh'oulder andthen so positioned relative to. the bar that thecross strap-2'? will clear the'barfor'movement. The present inventionis' characterized by the provision of friction means on the: bar 1 5 toaccomplish' the disengaging ofthelatc'h dogandalso'its re-setting-merely by, raising; and lowering movements of the desk top. These operations will'now be described? Starting with the desktop in a lowered, horizontal position-of rest and the latchbar i6 and latch dog in" the relationship in which they are shown'inF-igs. 2 and 3, andassuming that it is desired "toadjust the desk top forsupport-at'any one of its selectedangles of'support; the top israised by swinging its" free edge' upwardly about the hinge axis; the desk' top moves upwardly, the ban! 8- slides endivise through the latch, as guided by. the pivot member, and its free end moves towardthe latch dog. When the-desk top hasbeen raised'to such extent that the particular shoulder i! I that'is to be en'gaged by the dogjorsupport 'of'the top has passed through and slightly beyond the latch-dog, then thedesktop is slightly lowered; andthecross strap 2'? of'thelat'ch dog is engaged with the shoulder. To insure such engagement of the strap with-any selected shoulder, I have provided the bar IS with friction knobs 5%, well shown in Figs. 3 and 4. These knobs are of metal and in theform of hemispheres projecting inalignment from the opposite sidesof the bar It immediately above each of the shoulders All; These knobs project sufficient- 1y from the bar 'surfacethat incident to the shiftingof the bar-i6 lengthwise, and thepassing of anyiset cflmobs'between the opposite side plates of the latch dog, they will frictional-1y contact with the undersides of the outwardly yieldable spring strips Bl-t-l thus through them to drag the lowerend of the latch dog-in the direction of travel of the bar.

It is of importance to understand that if the desktop is swung upwardlyfrom any-position of support andythej-bar [S'isthereby causedto move to such extent that atleastone set of friction knobs is cause-alto pass from-a position below the latch dog tea-position above it; then reverse travel of the bar: is will cause the first set of knobs that engages the latch to swing it back into holding contact with. the: notch. shoulder adjacent that set of knobs. Howevenif the desk topismoyed upwardly only to suclilimited extent that the immediately adjacent knobs will engage the dog and swing it to that position of release, in which it is shown in Fig. 6, and no farther, then upon lowering movement of the top the dog will remain in that position and the bar IE will slide freely through the latch and will not be stopped until the latch is actuated to holdin position by the next higher set of knobs.

Therefore, it will be understood that if it is desired to lower the desk top from th full line position shown in Fig. 1 to the next lower dotted line position, it is only necessary to swing the desk top upwardly through a slight angle, thus to cause the friction knobs, which are then immedi ately below the latch lever to engage the spring strips, but not to pass beyond them, and rotate the latch dog, as from position of Fig. 5, to position of Fig. 6, then to lower the top. In the lowering, the bar l5 moves downwardly and the friction knobs merely disengage the latch dog without causing ire-setting movement. Therefore, the bar 16 can continue to move downwardly through the latch to bring the next higher notch thereof into position. When the friction knobs associated with this next higher notch come into frictional contact with the latch dog springs 3| they rotate the latch downwardly to holding position and its cross strap 21 engages with the notch shoulder, for example, as in Fig. '7 to support the top.

To release the latch dog as required for a further lowering of the desk top, it is only necessary to swing the top upwardly through that limited angle required to cause the friction knobs, which are then immediately below the latch lever, to again engage the spring strip and rotate the latch dog to a position of release, then to lower the top and cause the bar [5 to move downwardly through the latch and the next higher set of friction knobs thereon to be engaged with the spring strips 3| of the latch to swing it to holding position in the same manner as previously described.

Regardless of the angular position at which the desk top may be supported by the bar and latch dog, the latter may be released from the bar for a lowering adjustment of the top merely by effecting that slight upward swing of the top that causes the latch dog to be moved to release position but without the actuating knobs 50 passing the spring strips, then swinging the top downwardly.

Upward adjustment of the desk top from any position to full extent can be made without interruption, but positions of support are established only by first raising the top to a position slightly beyond the desired inclination, then lowering it to cause the friction knobs corresponding to that position of support, to engage and swing the latch dog to holding position.

The functional operations of the latch mechanism are by reason of the permitted slight turning of the dog on its pivotal support under the influence of the friction knobs associated with the latch bar as the latter is shifted.

The present device is simple in construction and mode of operation and is positive in its action. It is practical for the purpose described and for innumerable analogous uses. The accidental dropping of the raised desk to any extent is prevented by the automatic re-setting of the latch dog.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is:

1. In combination, a support, a movable top member associated therewith for raising and lowering movements and a catch mechanism for the support of said top member when in a raised position; said catch mechanism comprising a rigid bar pivotally connected at one end to the said top member for endwise travel in accordance with its raising and lowering movements, said bar being formed with a longitudinal slot and with notches in spaced relationship along an outer edge thereof, a pivot shaft mounted in the support and extended through said bar slot as a guide for the bar in its endwise travel, a latch dog pivoted on the said pivot shaft and extended across the bar at one side of its longitudinal slot and beyond its notched edge, and formed at its outer end with a transversely direct-ed part adapted to be selectively engaged in the bar notches to support the top member at definite raised positions of adjustment, and by angular adjustment of the latch dog relative to the bar to be disengaged from the notched edge of the bar for free travel of the bar, and means on the latch dog and on the bar that are frictionally engageable for the actuation of the latch dog to and from bar holding position by endwise movement of the bar in opposite directions.

'2. A combination as in claim 1 wherein the latch dog comprises spaced opposite side plates with their inner ends mounted on the pivot shaft at opposite sides of the bar and their outer ends joined by said transversely directed part thereof and wherein the said bar is slidable endwise between the opposite side plates of said dog.

3. A desk having a frame structure, a top member hinged thereto for raising to different angles of inclination, and a catch mechanism for support of said top member in a raised position; said catch mechanism comprising a rigid bar pivotally attached at one end to said top member at a substantial distance from the hinge and formed with a longitudinal slot and with notches in spaced relationship along one of its longitudinal edges, each notch providing a shoulder faced toward the free end of the bar, a pivot shaft fixed in the frame structure parallel with the hinge axis and substantially spaced therefrom, and passing through the bar slot as a guide for the bar in its endwise movements with the raising and lowering of the top member, a latch dog comprising spaced opposite side plates with inner ends mounted on the pivot shaft at opposite sides of the bar, and extended beyond the notched edge of the bar and joined across their outer ends by a shoulder engaging cross member that is selectively engageable with the notch shoulders for support of the top member at definite angles of inclination, and is disengageable from the shoulders for the free endwise movement of the bar, spring members associated with the latch dog and outwardly yieldable from the bar, and contact members on the bar corresponding to each of the notches therein, and adapted, with the endwise movements of the bar to be engaged with said spring member to actuate the latch dog about the pivot shaft to move the said cross-member thereof to and from shoulder engaging position.

4. A combination as recited in claim 3 wherein, in upward adjustment of the hinged top member from a raised position of support, the engaging of a contact member of the bar with the said spring members of the latch dog, swings the latch dog from holding to released position.

5. A combination as in claim 3 wherein, in any upward adjustment of the hinged top memher, the: engaging, (If acontact. member with the said spring members of the latchdog, swings the latch dog: to releasedposition, and the engaging of the contact member. with the spring. means of. the released latch in a downward adjustment of the raisedrtop membenswings the dog toaholding engagement with the shoulder of. the notch corresponding to that contact member.

6. In combination, a longitudinally movable bar, formed in one edge with a stop shoulder, and having a longitudinal slot, a. pivot shaft extended. throughv theslot as a guide for the bar in its longitudinal movements, and a latch dog pivctally mounted on the shaft and comprising spaced oppositesidernembers betweenwhich .the bar issiidably contained; said side members being joined at their. outer ends by a cross-piece adapted by an angular adjustment of the dog .tobe engaged w'iththe barshoulder to stop travel of the bar in one direction, a spring. strip contained longitudinally of and between the side members of the latch dog for .its angular adjustment and outwardly yieldable fromthe bar and by means of which strip. the latch dog can be 83 swung on the .pivot shaft'betweenbar. holding and bar releasingpositions, a contact button on the bar adapted, in passing the. dog, to engage frictionally with the said spring members, andfby such engagement in one direction of movement -ofthe bar, to swing the latch dog from a holding to a released position, and in moving in the opposite direction-of. travel, to swing the released latch to holding contact with: the shoulder and a spring washer disposed under compression about the pivot shaftv between a side member of the dog and said spring strip.

References Cited in theyfile of this patent UNITED STATES PATENTS 

